According to the historian Bede, Aidan was an Irish monk on the island of Iona when he was sent to preach the gospel in Northumbria after a period of pagan resurgence. Aidan established his headquarters on the island of Lindisfarne, where he founded a monastery to train English boys to become missionaries among their own people. He himself went about on foot, preaching and setting up missionary centers, which had the support of the king, Oswald of Northumbria.

Eventually, Lindisfarne became a great center of Celtic Christianity and a storehouse of European learning during the Dark Ages. It is where the Lindisfarne Gospels, an illuminated Latin manuscript of the gospels, were composed about 700.